Chicago/Rockford, Illinois · field elev 742 ft
Density Altitude at Chicago/Rockford International (KRFD)
Chicago/Rockford International sits at 742 ft, and even a typical July afternoon (84 °F) only lifts density altitude to about 2,517 ft — heat still trims performance, but the field rarely turns high-and-hot.
Typical density altitude by month
| Month | Avg temp °F | DA at avg temp | Afternoon high °F | DA on a typical afternoon |
|---|---|---|---|---|
| January | 21.8 | −1,614 ft | 29.1 | −1,095 ft |
| February | 25.6 | −1,343 ft | 33.4 | −794 ft |
| March | 37.3 | −524 ft | 46.5 | 104 ft |
| April | 49.1 | 278 ft | 59.7 | 980 ft |
| May | 60.4 | 1,025 ft | 71.2 | 1,721 ft |
| June | 70.1 | 1,651 ft | 80.7 | 2,318 ft |
| July | 73.8 | 1,886 ft | 83.9 | 2,517 ft |
| August | 71.9 | 1,765 ft | 82.0 | 2,399 ft |
| September | 64.4 | 1,285 ft | 75.3 | 1,980 ft |
| October | 52.0 | 472 ft | 62.3 | 1,149 ft |
| November | 38.8 | −421 ft | 47.1 | 144 ft |
| December | 27.3 | −1,222 ft | 34.3 | −732 ft |
▲ above 5,000 ft · ⚠ above 8,000 ft. These are planning references at standard pressure and dry air — afternoon humidity and low pressure both push the real number higher. Run today's values below.
Run today’s numbers for KRFD
DENSITY ALTITUDE
Field elevation 742 ft — the air behaves like 2,523 ft.
- PRESSURE ALT
- 743 ft
- ISA DEVIATION
- —
- RULE-OF-THUMB DA
- —
- AIR DENSITY INDEX
- —
- AIR DENSITY
- —
- WATER · GRAINS/LB
- —
For training and reference · verify with official sources and your POH before flight · no tool on this site renders a go / no-go judgment
Nearby Illinois fields
- 1C8 — Cottonwood
Rockford · elev 741 ft
- C77 — Poplar Grove
Poplar Grove · elev 857 ft
- C55 — Ogle County
Mount Morris · elev 929 ft
- KRPJ — Rochelle Municipal/Koritz Field
Rochelle · elev 781 ft
- KFEP — Albertus
Freeport · elev 859 ft
- KDKB — De Kalb Taylor Municipal
De Kalb · elev 913 ft
- 0C0 — Dacy
Harvard · elev 913 ft
- C82 — Bresson
Compton · elev 769 ft
Frequently asked questions
How high does density altitude get at KRFD in summer?
On a typical July afternoon — around 84 °F at the nearest NOAA normals station — density altitude at Chicago/Rockford International reaches roughly 2,517 ft at standard pressure. Hotter-than-normal days, low pressure, and humidity all push it higher, so run the day's actual numbers before flying.
What is the density altitude at KRFD on an average day?
It swings with the seasons: from roughly −1,614 ft at the coldest month's average temperature to about 1,886 ft at the warmest month's — all from a constant field elevation of 742 ft. The month-by-month table above carries the full year.
What is the field elevation of Chicago/Rockford International?
742 ft MSL, from the FAA NASR airport record (28-day cycle effective 2026-08-06). The identifier is KRFD (ICAO) / RFD (FAA), in Chicago/Rockford, Illinois.